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Molecular characterization of mitocalcin, a novel mitochondrial Ca 2+ ‐binding protein with EF‐hand and coiled‐coil domains
Author(s) -
Tominaga Mitsutoshi,
Kurihara Hidetake,
Honda Shinya,
Amakawa Genta,
Sakai Tatsuo,
Tomooka Yasuhiro
Publication year - 2006
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2005.03554.x
Subject(s) - neurite , mitochondrion , immunogold labelling , microbiology and biotechnology , biology , cerebellum , western blot , biochemistry , ultrastructure , neuroscience , anatomy , gene , in vitro
Here we have identified and characterized a novel mitochondrial Ca 2+ ‐binding protein, mitocalcin. Western blot analysis demonstrated that mitocalcin was widely expressed in mouse tissues. The expression in brain was increased during post‐natal to adult development. Further analyses were carried out in newly established neural cell lines. The protein was expressed specifically in neurons but not in glial cells. Double‐labeling studies revealed that mitocalcin was colocalized with mitochondria in neurons differentiated from 2Y‐3t cells. In addition, mitocalcin was enriched in the mitochondrial fraction purified from the cells. Immunohistochemical studies on mouse cerebellum revealed that the expression pattern of mitocalcin in glomeruli of the internal granular and molecular layers was well overlapped by the distribution pattern of mitochondria. Immunogold electron microscopy showed that mitocalcin was associated with mitochondrial inner membrane. Overexpression of mitocalcin in 2Y‐3t cells resulted in neurite extension. Inhibition of the expression in 2Y‐3t cells caused suppression of neurite outgrowth and then cell death. These findings suggest that mitocalcin may play roles in neuronal differentiation and function through the control of mitochondrial function.